Interface insertion anomaly detection circuit and method

ABSTRACT

Provided are an interface insertion anomaly detection circuit and method applicable to the field of mobile terminals. The interface insertion anomaly detection circuit comprises a power circuit ( 4 ), and further comprises: a first USB interface ( 1 ), comprising a first power line and a first signal line, a power end of the first power line being connected to the power circuit ( 4 ); a second USB interface ( 2 ), comprising a second power line and a second signal line, the second power line and the second signal line being short-circuit connected, wherein the second USB interface ( 2 ) connects the second signal and the first signal line through insertion to the first USB interface ( 1 ); and a controller ( 3 ), a first voltage collection end and a second voltage collection end thereof being respectively connected to the power end of the first power line and a signal end of the first signal line. The controller ( 3 ) can determine, according to a calculated voltage difference, whether the first power line and the second power line are well connected by insertion, and then determine whether to start or resume charging a cell of a mobile terminal through the first USB interface ( 1 ) and the second USB interface ( 2 ).

TECHNICAL FIELD

The present disclosure generally relates to the mobile terminal field, and more particularly, to a detection circuit and a method for detecting an abnormal interface coupling.

BACKGROUND

With the progress of the times, the internet and mobile communication network provide massive functions and applications. A user not only can use a mobile terminal to perform conventional applications, such as use a smart phone to answer a call or call somebody up, but also can use the mobile terminal to browse a webpage, transmit a picture or play a game and so on.

When the mobile terminal is used to handle matters, a huge quantity of electricity in a cell of the mobile terminal is consumed due to the increased usage frequency of the mobile terminal, such that it is required to charge the mobile terminal frequently. Since the pace of life becomes more and more fast, particularly, emergencies become more and more frequent, the user wants to charge the cell of the mobile terminal with large current.

With the increasing usage frequency of the mobile terminal, it is required to charge the mobile terminal frequently. If the mobile terminal is charged anomalously due to an abnormal USB interface coupling, it is easy to cause a safety accident, which may damage the USB interface, the mobile terminal or the charging adapter, or even cause a fire. Therefore, there is a need to detect whether there is the USB interface coupling is abnormal after the USB interfaces are coupled.

SUMMARY

An objective of the present disclosure is to provide a detection circuit and a method for detecting an abnormal interface coupling, which may detect whether the USB interface coupling is abnormal after the USB interfaces are coupled.

In one aspect, the present disclosure provides a detection circuit for detecting an abnormal interface coupling. The detection circuit includes a power circuit, and further includes:

a first USB interface, including a first power wire and a first signal wire, in which a power end of the first power wire is coupled to the power circuit;

a second USB interface, including a second power wire and a second signal wire; in which, the second power wire and the second signal wire are short-circuited coupled; the second USB interface is coupled with the first USB interface, such that the second signal wire is coupled with the first signal wire; the first power wire is configured to receive a power signal outputted by the power circuit, and to output the power signal to the second power wire in the second USB interface coupled with the first USB interface; and

a controller, including a first voltage sampling end coupled to the power end of the first power wire in the first USB interface, and a second voltage sampling end coupled to a signal end of the first signal wire in the first USB interface; and configured to acquire a voltage of the first power wire and a voltage of the first signal wire in the first USB interface through the coupling between the first USB interface and the second USB interface, to calculate a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and to determine whether the interface coupling is abnormal according to the voltage difference.

In another aspect, the present disclosure provides a method for detecting an abnormal interface coupling. The method is applied in a detection circuit for detecting an abnormal interface coupling including a controller, a first USB interface, a second USB interface and a power circuit. A first signal wire in the first USB interface is coupled with a second signal wire in the second USB interface when the first USB interface is coupled with the second USB interface. The method includes:

short-circuited coupling a second power wire in the second USB interface with the second signal wire in the second USB interface;

outputting by the power circuit a power signal to a first power wire in the first USB interface when the first USB interface is coupled with the second USB interface, such that the first USB interface outputs the power signal to the second power wire in the second USB interface via the first power wire; and

with the controller, detecting a voltage of the first power wire in the first USB interface and a voltage of the first signal wire in the first USB interface, calculating a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and determining whether a coupling between the first USB interface and the second USB interface is abnormal according to the voltage difference.

The advantageous effect of the present disclosure is that, when the first USB interface is coupled with the second USB interface, the voltage of the first signal wire in the first USB interface is approximately equal to the voltage of the second signal wire in the second USB interface, as long as the first signal wire in the first USB interface is coupled with (rather than disconnected from) the second signal wire in the second USB interface. Moreover, since the second power wire and the second signal wire are short-circuited coupled, when the power circuit outputs the power signal to the second power wire via the first power wire, the voltage of the first signal wire acquired by the controller is also the voltage of the second power wire, such that the voltage difference (the voltage difference between the voltage of the first power wire and the voltage of the first signal wire) calculated by the controller is also the voltage difference between the voltage of the first power wire in the first USB interface and the voltage of the second power wire in the second USB interface. Then, the controller may determine whether the first power wire is well coupled with the second power wire according to the voltage difference calculated, and further determine whether it can start or continue charging the cell of the mobile terminal through the first USB interface and the second USB interface.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to make the technical solutions of embodiments of the present invention more clearly, the accompanying drawings used in the description of embodiments of the present invention are briefly described hereunder. Obviously, the described drawings are merely some embodiments of present invention. For persons skilled in the art, other drawings may be obtained based on these drawings without any creative work.

FIG. 1 is a schematic diagram of a detection circuit for detecting an abnormal interface coupling according to an embodiment of the present disclosure.

FIG. 2 is a first flow chart showing a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure.

FIG. 3 is a second flow chart showing a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure.

FIG. 4 is a third flow chart showing a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

To make the objectives, the technical solutions, and the advantages of embodiments of the present invention clearer, the technical solutions in embodiments of the present invention are hereinafter described clearly and completely with reference to the accompanying drawings in embodiments of the present invention. Apparently, the described embodiments are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. In order to explain the technical solutions of the present disclosure, specific embodiments will be described as follows.

It should be noted that, a charging adapter in embodiments of the present disclosure includes a terminal capable of outputting a power signal to charge a cell (a cell of a mobile terminal), such as a power adapter, a charger, an IPAD and a smart phone.

It should be noted that, “first” used in “first USB interface”, “first power wire”, “first ground wire” and “first signal wire” is used herein for purposes of description, “second” used in “second USB interface”, “second power wire”, “second ground wire” and “second signal wire” is also used herein for purposes of description.

In an embodiment of the present disclosure, when a charging adapter is used to charge a mobile terminal, it is required to detect whether a coupling between the first USB interface 1 and the second USB interface 2 is abnormal, especially, whether a first power wire in the first USB interface 1 is well coupled with a second power wire in the second USB interface 2. If the coupling is abnormal, then the mobile terminal is not charged. The mobile terminal is charged, particularly with large current (3A or greater than 3A), only when the coupling is normal, especially when the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2 and a first ground wire in the first USB interface 1 is well coupled with a second ground wire in the second USB interface 2.

FIG. 1 shows a specific diagram of a detection circuit for detecting an abnormal interface coupling according to an embodiment of the present disclosure. For facilitating the explanation, only parts related to this embodiment of the present disclosure are shown, which may be described as follows.

The present disclosure provides a detection circuit for detecting an abnormal interface coupling. The detection circuit includes a power circuit 4, and further includes a first USB interface 1, a second USB interface 2 and a controller 3.

The first USB interface 1 includes a first power wire and a first signal wire. A power end of the first power wire is coupled with the power circuit 4.

The second USB interface 2 includes a second power wire and a second signal wire. The second power wire and the second signal wire are short-circuited coupled. The second USB interface 2 is coupled with the first USB interface 1, such that the second signal wire is coupled with the first signal wire. The first power wire is configured to receive a power signal outputted by the power circuit 4, and to output the power signal received to the second power wire in the second USB interface 2 coupled with the first USB interface 1.

The controller 3 includes a first voltage sampling end coupled to the power end of the first power wire in the first USB interface 1 and a second voltage sampling end coupled to a signal end of the first signal wire in the first USB interface 1. The controller 3 is configured to acquire a voltage of the first power wire in the first USB interface 1 and a voltage of the first signal wire in the first USB interface 1 through the coupling between the first USB interface 1 and the second USB interface 2, to calculate a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and to determine whether the interface coupling is abnormal according to the voltage difference.

In this embodiment, if a charging adapter is used to charge the mobile terminal, the power circuit 4 starts outputting the power signal to the second power wire in the second USB interface 2 via the first power wire in the first USB interface 1, after the user couples the first USB interface 1 with the second USB interface 2.

Since a signal wire transmits a signal with small current, when the first USB interface 1 is coupled with the second USB interface 2, it may be considered that the voltage of the first signal wire in the first USB interface 1 is approximately equal to the voltage of the second signal wire in the second USB interface 2, as long as the first signal wire in the first USB interface 1 is coupled with the second signal wire in the second USB interface 2, even though the coupling between the first signal wire in the first USB interface 1 and the second signal wire in the second USB interface 2 is not good enough.

Further, the controller 3 acquires the voltage of the first power wire in the first USB interface 1 from the first voltage sampling end, and acquires the voltage of the first signal wire in the first USB interface 1 from the second voltage sampling end. Since the second power wire and the second signal wire in the second USB interface 2 are short-circuited coupled, the voltage of the first signal wire acquired by the controller 3 is also the voltage of the second power wire in the second USB interface 2, such that the voltage difference (the voltage difference between the voltage of the first power wire and the voltage of the first signal wire) calculated by the controller 3 is also the voltage difference between the voltage of the first power wire in the first USB interface 1 and the voltage of the second power wire in the second USB interface 2.

Further, the controller 3 may determine whether the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2 according to the voltage difference between the voltage of the first power wire and the voltage of the first signal wire. Specifically, if the voltage difference between the voltage of the first power wire and the voltage of the first signal wire is less than or equal to a preset voltage threshold, it means that the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2, such that the cell of the mobile terminal may be charged. If the voltage difference between the voltage of the first power wire and the voltage of the first signal wire is greater than the preset voltage threshold, it means that the first power wire in the first USB interface 1 is not well coupled with the second power wire in the second USB interface 2, such that the cell of the mobile terminal cannot be charged. Preferably, if the voltage difference between the voltage of the first power wire and the voltage of the first signal wire is greater than the preset voltage threshold, the controller 3 sends a detection stop instruction to the power circuit 4, so as to control the power circuit 4 to stop outputting the power signal to the first power wire in the first USB interface 1.

It should be noted that, the preset voltage threshold is set at least according to the following values: the voltage difference between the voltage of the first power wire and the voltage of the first signal wire calculated when the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2, and the current outputted by the power circuit 4 to the second power wire via the first power wire when the coupling is detected.

Preferably, even though the cell of the mobile terminal is charged since the coupling between the first USB interface 1 and the second USB interface 2 is good at first, the controller 3 still acquires the voltage of the first power wire and the voltage of the first signal wire in the first USB interface 1 respectively in real time, calculates the voltage difference between the voltage of the first power wire and the voltage of the first signal wire in real time, and determines whether the coupling is abnormal according to the voltage difference in real time. If the coupling is abnormal, the controller 3 may send a detection stop instruction to the power circuit 4 in time, so as to control the power circuit 4 to stop outputting the power signal to the first power wire in the first USB interface 1.

In another embodiment of the present disclosure, the detection circuit further includes an alarm circuit 5.

A controlled end of the alarm circuit 5 is coupled with a control end of the controller 3. If the voltage difference between the voltage of the first power wire in the first USB interface 1 and the voltage in the first signal wire in the first USB interface 1 is greater than the preset voltage threshold, the alarm circuit 5 receives a prompt instruction sent from the controller 3 and issues the alarm.

Thus, if the first power wire in the first USB interface 1 is not well coupled with the second power wire in the second USB interface 2, the voltage difference between the voltage of first power wire in the first USB interface 1 and the voltage of the first signal wire in the first USB interface 1 is greater than the preset voltage threshold, such that the controller 3 controls the power circuit 4 to stop outputting the power signal to the first power wire in the first USB interface 1, and meanwhile sends a prompt instruction to the alarm circuit 5, and then the alarm circuit 5 issues the alarm. Preferably, the alarm circuit 5 may issue the alarm by the following ways of: controlling an LED light to illumine or flash, and/or controlling a speaker to make sound and so on.

It should be noted that, if there is a need to charge the mobile terminal by a charging adapter, it is required to couple a USB plug included in the charging adapter with a USB socket included in the mobile terminal, such that the cell of the mobile terminal is charged after the detection circuit for detecting an abnormal interface coupling detects that the USB plug is well coupled with the USB socket.

In another embodiment of the present disclosure, the first USB interface 1 is a USB socket, and the power circuit 4, the first USB interface 1 and the controller 3 are included in the mobile terminal.

The second USB interface 2 is a USB plug, and the second USB interface 2 is included in the charging adapter.

In this way, it may be detected by the mobile terminal whether the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2.

In another embodiment of the present disclosure, the first USB interface 1 is a USB plug, and the power circuit 4, the first USB interface 1 and the controller 3 are included in the charging adapter.

The second USB interface 2 is a USB socket, and the second USB interface 2 is included in the mobile terminal.

In this way, it may be detected by the charging adapter whether the first power wire in the first USB interface 1 is well coupled with the second power wire in the second USB interface 2.

In another embodiment of the present disclosure, the number of the first power wires in the first USB interface 1 is P, and P is greater than or equal to 2.

The first USB interface 1 further includes Q first ground wires, and Q is greater than or equal to 2.

It should be noted that, since a MICRO USB interface in an existing mobile terminal only includes one power wire and one ground wire, the mobile terminal is charged only through one charging loop formed by one power path and one ground path when the mobile terminal is charged via the MICRO USB interface, such that the maximum charging current supported is just 3A, and therefore the charging is slow and wastes time.

On the basis of this, the first USB interface 1 provided by an embodiment of the present disclosure includes P first power wires and Q first ground wires, such that if there are at least two second power wires and at least two ground wires in the second USB interface 2, at least two charging loops may be formed when the first USB interface 1 is coupled with the second USB interface 2, and thus the charging current at least greater than 3A may be supported. In addition, if the second USB interface 2 is a common MICRO USB interface, it can be compatible with the first USB interface 1 above and the charging may be performed.

In another embodiment of the present disclosure, the number of the second power wires in the second USB interface 2 is M, and M is greater than or equal to 2.

The second USB interface 2 further includes N second ground wires, and N is greater than or equal to 2.

Similarly, the second USB interface 2 provided by an embodiment of the present disclosure includes M second power wires and N second ground wires, such that if there are at least two first power wires and at least two first ground wires in the first USB interface 1, at least two charging loops may be formed when the first USB interface 1 is coupled with the second USB interface 2, and thus the charging current at least greater than 3A may be supported. In addition, if the first USB interface 1 is a common MICRO USB interface, it can be compatible with the second USB interface 2 above and the charging may be performed.

In another embodiment of the present disclosure, P, M, Q and N are identical to each other.

The first power wire included in the first USB interface is made of chromium bronze C18400 or phosphor bronze C7025, the first ground wire included in the first USB interface is made of chromium bronze C18400 or phosphor bronze C7025, the second power wire included in the second USB interface is made of chromium bronze C18400 or phosphor bronze C7025, and the second ground wire included in the second USB interface is made of chromium bronze C18400 or phosphor bronze C7025.

It should be noted that, each of the power wire and the ground wire in the existing MICRO USB interface is made of metal copper foil with conductivity less than 20%. However, each of the first power wire and the first ground wire included in the first USB interface 1, the second power wire and the second ground wire included in the second USB interface 2 is made of phosphor bronze C7025 with conductivity reaching 50%, such that the charging current may be further increased in the case that the cell of mobile terminal is charged using at least two charging loops (including at least two first power wires, at least two first ground wires, at least two second power wires and at least two second ground wires). More preferably, each of the first power wire and the first ground wire included in the first USB interface 1, the second power wire and the second ground wire included in the second USB interface 2 is made of chromium bronze C18400 with conductivity reaching 70%, which may further increases the charging current.

FIG. 2 shows a first flow chart of a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure. For facilitating the explanation, only parts related to this embodiment of the present disclosure are shown, which may be described as follows.

It should be noted that, the interface coupling detection method provided by an embodiment of the present disclosure and the interface coupling detection circuit provided by an embodiment of the present disclosure are adaptable to each other.

The method for detecting an abnormal interface coupling provided by an embodiment of the present disclosure may be applied in a detection circuit for detecting an abnormal coupling including a controller, a first USB interface, a second USB interface and a power circuit 4. When the first USB interface is coupled with the second USB interface, a first signal wire in the first USB interface is coupled with a second signal wire in the second USB interface. The method for detecting an abnormal interface coupling includes following steps.

A second power wire in the second USB interface and a second signal wire in the second USB interface are short-circuited coupled.

The power circuit 4 outputs a power signal to a first power wire in the first USB interface when the first USB interface is coupled with the second USB interface, such that the first USB interface outputs the power signal to the second power wire in the second USB interface via the first power wire.

The controller detects a voltage of the first power wire in the first USB interface and a voltage of the first signal wire in the first USB interface, calculates a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and determines whether a coupling between the first USB interface and the second USB interface is abnormal according to the voltage difference.

It should be noted that, if a charging adapter is used to charge the mobile terminal, the user may couple the first USB interface with the second USB interface. As long as the first signal wire is not disconnected from (i.e., coupled to) the second signal wire, it can be considered that the voltage of the first signal wire in the first USB interface is approximately equal to the voltage of the second signal wire in the second USB interface.

When the controller acquires the voltage of the first power wire and the voltage of the first signal wire in the first USB interface, the voltage of the first signal wire acquired by the controller is also the voltage of the second power wire in the second USB interface since the second power wire and the second signal wire in the second USB interface are short-circuited coupled, such that the voltage difference (the voltage difference between the voltage of the first power wire and the voltage of the first signal wire) calculated by the controller is also the voltage difference between the voltage of the first power wire in the first USB interface and the voltage of the second power wire in the second USB interface.

Thus, the controller may determine whether the coupling between the first power wire in the first USB interface and the second power wire in the second USB interface is abnormal according to the voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and thus determine whether the coupling between the first USB interface and the second USB interface is abnormal.

FIG. 2 shows a second flow chart of a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure. For facilitating the explanation, only parts related to this embodiment of the present disclosure are shown, which may be described as follows.

In another embodiment of the present disclosure, the method for detecting the abnormal interface coupling further includes the following step.

If the voltage difference between the voltage of the first power wire in the first USB interface and the voltage of the first signal wire in the first USB interface is greater than a preset voltage threshold, the controller controls an alarm circuit to issue an alarm, and sends a detection stop instruction to the power circuit so as to control the power circuit to stop outputting the power signal to the first power wire in the first USB interface.

In this way, either when the first USB interface is being coupled with the second USB interface or when the charging is being performed after the interface coupling is detected, the controller controls the power circuit to stop outputting the power signal to the first power wire in the first USB interface and controls the alarm circuit to issue the alarm, once the voltage difference between the voltage of the first power wire and the voltage of the first signal wire in the first USB interface is greater than the preset voltage threshold, in order to avoid the damage of USB interface (the first USB interface and the second USB interface) due to an abnormal coupling.

FIG. 3 shows a third flow chart of a method for detecting an abnormal interface coupling according to an embodiment of the present disclosure. For facilitating the explanation, only parts related to this embodiment of the present disclosure are shown, which may be described as follows.

In another embodiment of the present disclosure, after the controller controls the alarm circuit to issue the alarm, the method for detecting the abnormal interface coupling further includes the following step.

After a preset time period, the controller sends a detection instruction to the power circuit, such that the power circuit outputs the power signal to the first power wire in the first USB interface.

Specifically, when an abnormal coupling occurs, the user may couple the first USB interface with the second USB interface again after the alarm circuit has issued the alarm. Accordingly, after the power circuit stops outputting the power signal to the first power wire in the first USB interface, the controller sends the detection instruction to the power circuit every the preset time period, such that the power circuit outputs the power signal to the first power wire in the first USB interface, and the controller acquires the voltage of the first power wire in the first USB interface and the voltage of the second power wire in the second USB interface again and calculates the voltage difference, and determines whether the first power wire in the first USB interface is well coupled with the second power wire in the second USB interface according to the voltage difference.

In conclusion, the charging is performed, particularly with large current (greater than 3A), only if the first USB interface is well coupled with the second USB interface.

The embodiments described hereinabove are only preferred embodiments of the present application, and should not be interpreted as limitation to the present application. For the persons skilled in the art, various variations and modifications may be made to the present application. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present application are also deemed to fall into the protection scope of the present application. 

What is claimed is:
 1. A detection circuit for detecting an abnormal interface coupling, comprising a power circuit, and being characterized at, further comprising: a first USB interface, comprising a first power wire and a first signal wire, wherein a power end of the first power wire is coupled to the power circuit; a second USB interface, comprising a second power wire and a second signal wire, wherein the second power wire and the second signal wire are short-circuited coupled; the second USB interface is coupled with the first USB interface, such that the second signal wire is coupled with the first signal wire; the first power wire is configured to receive a power signal outputted by the power circuit, and to output the power signal received to the second power wire in the second USB interface coupled with the first USB interface; and a controller, comprising a first voltage sampling end coupled to the power end of the first power wire in the first USB interface, and a second voltage sampling end coupled to a signal end of the first signal wire in the first USB interface; and configured to acquire a voltage of the first power wire and a voltage of the first signal wire in the first USB interface through a coupling between the first USB interface and the second USB interface, to calculate a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and to determine whether the interface coupling is abnormal according to the voltage difference.
 2. The detection circuit according to claim 1, being characterized at that, further comprising: an alarm circuit, comprising a controlled end coupled to a control end of the controller; and configured to receive a prompt instruction sent by the controller and to issue an alarm, if the voltage difference between the voltage of the first power wire and the voltage of the first signal wire is greater than a preset voltage threshold.
 3. The detection circuit according to claim 1, being characterized at that, the first USB interface is a USB socket, and the power circuit, the first USB interface and the controller are included in a mobile terminal; and the second USB interface is a USB plug and included in a charging adapter.
 4. The detection circuit according to claim 1, being characterized at that, the first USB interface is a USB plug, the power circuit, the first USB interface and the controller are included in a charging adapter; and the second USB interface is a USB socket and included in a mobile terminal.
 5. The detection circuit according to any one of claims 1-4, being characterized at that, the first USB interface comprises P first power wires, where P is greater than or equal to 2; and the first USB interface further comprises Q first ground wires, where Q is greater than or equal to
 2. 6. The detection circuit according to claim 5, being characterized at that, the second USB interface comprises M second power wires, where M is greater than or equal to 2; and the second USB interface comprises N second ground wires, where N is greater than or equal to
 2. 7. The detection circuit according to claim 6, being characterized at that, P, M, Q and N are identical to each other; each first power wire in the first USB interface is made of chromium bronze C18400 or phosphor bronze C7025, each first ground wire in the first USB interface is made of chromium bronze C 18400 or phosphor bronze C7025, each second power wire in the second USB interface is made of chromium bronze C18400 or phosphor bronze C7025, and each second ground wire in the second USB interface is made of chromium bronze C18400 or phosphor bronze C7025.
 8. A method for detecting an abnormal interface coupling, applied in a detection circuit for detecting an abnormal interface coupling comprising a controller, a first USB interface, a second USB interface and a power circuit, a first signal wire in the first USB interface being coupled with a second signal wire in the second USB interface when the first USB interface is coupled with the second USB interface, and being characterized at that, the method comprises: short-circuited coupling a second power wire in the second USB interface with the second signal wire in the second USB interface; outputting by the power circuit a power signal to a first power wire in the first USB interface when the first USB interface is coupled with the second USB interface, such that the first USB interface outputs the power signal to the second power wire in the second USB interface via the first power wire; and detecting by the controller a voltage of the first power wire in the first USB interface and a voltage of the first signal wire in the first USB interface, calculating a voltage difference between the voltage of the first power wire and the voltage of the first signal wire, and determining whether a coupling between the first USB interface and the second USB interface is abnormal according to the voltage difference.
 9. The method according to claim 8, being characterized at that, further comprising: controlling by the controller an alarm circuit to issue an alarm, and sending a detection stop instruction to the power circuit for controlling the power circuit to stop outputting the power signal to the first power wire in the first USB interface, if the voltage difference between the voltage of the first power wire and the voltage of the first signal wire is greater than a preset voltage threshold.
 10. The method according to claim 9, being characterized at that, after controlling by the controller an alarm circuit to issue an alarm, further comprising: sending by the controller a detection instruction to the power circuit after a preset time period, such that the power circuit outputs the power signal to the first power wire in the first USB interface. 